Plaster of paris bandage and method of preparing same



April 3, 1934.- REREED 1,953,898

PLASTER PARIS BANDAGE AND METHOD OF PREPARING SAME Filed March 15, 1951PATENT OFFICE PLASTER OF PARIS BANDAGE AND METHOD OF PREPARING SAMERaymond E. Reed, Chicago, 111., assignor to The Kendall Company, ofMassachusetts Chicago, 111., a corporation Application March .13, 1931,Serial No. 522.494

' 5 Claims. (01. 128-91) This invention relates to a plaster of Parisbandage adapted for use in making surgical casts, and to a method ofpreparing the same for shipment and handling.

Bandages of the type referred to are ordinarily made by spreading theplaster in powdered or finely divided condition over strips of looselywoven fabric, such asgauze or crinoline, which are then wound into rollsof size suitable for casting purposes. In some cases the plaster,instead of being applied to the gauze in dry condition, is applied inthe form of a thin paste which, when dried, leaves the plaster in theform of a more or less continuous crust or coating. This type, however,is inconvenient to handle in the making of the cast, because of thetendency for the coils of the roll to telescope and become tangled whenthe roll is immersed in water preparatory to making the cast. Also thebandages whichcontain the plaster in finely divided condition are verymessy. When the roll is removed from the carton by the physician, looseplaster is likely to fall over his hands.

The object of my invention is to provide a plaster of Paris bandageconsisting of a neat, dustproof unit which may be easily handled bythe"physician without danger of losing any considerable part of the plasterin applying the bandage andwithout encountering the trouble caused byunwinding and telescoping of the coils thereof; also to provide a novelmethod of producing such a bandage.

The invention will be understood from the fol-'- lowing detaileddescription, which, taken in connection'with the accompanying drawing,discloses a preferred embodiment thereof.

Referring to the drawing:

Fig. 1 is a perspective view of a surgical bandage constructed accordingto my invention, an outer portion of the to show the internal structure;and.

Fig. 2 is a view of the cated by line 2-2 of Fig. l.

Generally stated, the invention resides in the provision of a thinprotective coating on the surfaces of the ordinary rolled plaster ofParis bandage. The coating comprises material which has sufficientadhesive properties to hold the rolled unit in wound-up condition andwhich is easily penetrated by water when the bandage is dippedpreparatory to use.

In the drawing, numeral 3 designates generally an ordinary form ofrolled plaster of Paris bandage consisting of a series of fabric coils 4containing plaster either in powdered form or in the form of anencrusting coating. In the ordinary form in which rolls of this type aremarketed the' fabric may be unwound while the bandage is in the drycondition, the entire put-up being more or-less loose, so that care mustbe bandage being broken away bandage taken as inditaken in dipping thebandageto prevent telescoping of the coils. The protective coating whichis applied to a roll of this type, in accordance with my invention, isindicated by the numeral 5, and is present in the form of a thin layerwhich covers both the end surfaces of the roll as well as the inner andouter cylindrical side walls.

The coating 5 is preferably applied by dipping the rolled bandage in asolution of a material which, when dried, will be easily penetrated bywater, and which in the dry condition will have sufficient adhesiveproperties to hold the coils together as a compact dust-proof unit. Thesolution of the adhesive material into which the rolled bandages aredipped, also preferably contains plaster of Paris in an amountsufficient to give thesolution the consistency of a thin paste.

The following is an example of a preferred composition for the dippingsolution:

' Pounds Gelatine (agar-agar) 5 Ammonium acetates; 6 Plaster of Paris105 Water 220 Thegelatine is added to the water and heated to boiling,and the solution is then cooled. The ammonium acetate is then dissolvedin the solution, after which the plaster in powdered form is introducedwith thorough stirring. This solution has the consistency of a thinpaste. The coating .5 is applied by dipping the rolled bandages in thissolution and then drying.

The gelatine in the above formula constitutes the adhesive materialwhich holds together the plaster in the dried coating to form a toughnonchipping protective surface. It is not necessary, however, to useplaster of Paris in the above formula inasmuch as the gelatine alonewill form an adhesive coating. When omitting plaster of Paris from thesolution, the procedure is substantially the same as above outlined, thebandages being dipped in the solution of gelatine and ammonium acetate,and then dried.

The ammonium acetate serves as a retardent to prevent prematurehardening of the plaster. Even though no plaster is used in the dippingsolution, a retardent is desirable to prevent premature hardening of theplaster on the outer surfaces of the roll which are moistened when thebandage is dipped. The'ammonium acetate, being volatile, is not presentin the final coating, it being driven off with the water in the dryingoperation. v

A firm and satisfactory'adhesive coating may be provided withoutfollowing strictly the above.- outlined preferred procedure. Forexample, it is not necessary that the solution of gelatine be firstboiled before incorporating the retardent and before adding the plaster.Also, it is not necessary to use a retardent. However, when theretardent is omitted, it is necessary to work the process at atemperature of 98 centrigrade, or higher, to prevent prematurehardening. As an example of this latter procedure, the following isgiven:

The rolled bandages are preliminarily heated to a temperature of about98 centrigrade, and are then dipped in a boiling solution comprising thefollowing mixture:

Pounds Gum arabic 2 Plaster of Paris 50 Water 100 The dipped bandagesare dried at a temperature not lower than 98 centrigrade.

The coating obtained by following any one of the above outlinedprocedures will bind together the coils of the roll to prevent fallingof loose plaster from the bandage. If plaster is used in the dippingsolution, a somewhat heavier coating is formed than will be formed bythe adhesive material alone. Either type of coating, however, willeffectively prevent loss of plaster and uncoiling of the roll when it isbeing made ready for use.

Various adhesive materials in addition to the gelatine and gum arabic,indicated in the above examples, may be used, among which may bementioned sugar, dextrine, starch, and various water-soluble gums, suchas gum ghatti. Also various ammonium salts such as ammonium carbonate,ammonium bicarbonate, ammonium hypophosphate, ammonium chloride, andammonium citrate, may be used as retardents in lieu of the ammoniumacetate in the above examples.

The invention provides a plaster bandage which is exceedingly convenientto handle, and which also is not likely to be affected by moisture inthe air, by reason of the protection afforded by the outer protectivecovering. The method of treatment is easily carried out and requiresonly the use of materials which are comparatively cheap. The driedcoating is very thin and is easily penetrated by water when the roll isimmersed, thereby avoiding any delay or inconvenience in handling whenthe bandage is being made ready for casting purposes.

While said coating is water-permeable, how ever, it does not readilybreak down even after immersion in water, and therefore prevents anexcess of water from entering between the layers of the roll, thusmaking it unnecessary to squeeze or wring out the roll after immersion,as is necessary with the ordinary plaster of Paris bandage. Greatdifficulty has heretofore been experienced by reason of the fact thatupon immersion the roll becomes super-saturated and is likely totelescope in the hands of the surgeon due to the fact that theplaster-coated layers are rendered slippery'and unruly for handling. Inaddition to the danger of ,telescoping, the usual form of bandagebecdmes very messy in the process of removing the excess water, thusmaking it extremely difficult to apply the bandage. Both thesedifficulties are overcome by my invention since the coating, whilesufficiently permeable to permit enough water to enter the roll tomoisten the plaster, does not disintegrate upon immersion, and thereforeprevents an excess of water from' entering between the layers of theroll, thus avoiding any necessity for wringing out the roll andpreventing telescoping of the latter.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible, in view of the prior art.

What I regard as new and desire to secure by Letters Patent is:

1. The method of forming a protective coating on the exterior surface ofa surgical bandage consisting of a rolled fabric strip having plaster ofParis incorporated therein, which comprises preliminarily heating thebandage, dipping the heated bandage in a mixture of plaster of Paris anda boiling solution of a water-soluble adhesive material, and drying thedipped bandage while maintaining the same in heated condition.

2. The method of forming a protective coating on the exterior surface ofa surgical bandage consisting of a rolled fabric strip having plaster ofParis incorporated therein, which comprises preliminarily heating thebandage to a temperature of about 98 centigrade, dipping the heatedbandage in a mixture of plaster of Paris and a boiling solution of awater-soluble adhesive material, and drying the dipped bandage at atemperature not lower than 98 centigrade.

3. A surgical bandage comprising a roll of fabric impregnated withplaster of Paris and designed for immersion in water prior to use, andcombined therewith a thin coating of water-permeable material appliedthereon for preventing unrolling of the bandage and the escape of theplaster from the bandage prior to and during immersion, said permeablecoating. being resistant to disintegration during immersion to aid inmaintaining the convolutions of the rolled bandage against telescopingduring and after immersion incidental to its use, said coatingpermitting the penetration of water therethrough to the extent necessaryto adequately moisten the plaster carried by the roll.

4. A surgical bandage comprising a roll of fabric having itsconvolutions impregnated with plaster of Paris in a dry comminuted stateand designed for immersion in water prior to use, said roll havingcombined therewith means for preventing unwinding of the roll and theescape of plaster therefrom, said means consisting of a thin coating ofwater-permeable material applied to the exposed surfaces of the roll andbeing resistant to disintegration during immersion to aid in maintainingthe convolutions of the rolled bandage against telescoping during andafter immersion as an incident to the use of the bandage.

5. A surgical bandage comprising a roll of fabric incorporating plasterof Paris and designed for immersion in water prior to use, and combinedtherewith a thin coating of water-per meable material consisting of anadhesive, watersoluble gum applied to the surface of the roll forpreventingvunrolling of the latter and the escape of the plastertherefrom prior to and during immersion, said permeable coating beingresistant to premature disintegration during immersion to aid inmaintaining the an nof the rolled bandage against telescoping during andafter immersion incidental to its use, said coating permitting thepenetration of water therethrough to the extent necessary to adequatelymoisten the plaster carried by the roll.

RAYMOND E. REED.

